🔍 Key Concepts
• Overall length is the sum of all the straight sections plus the unknown tapered length X.
• Dimensions A, B, C, and D are all shown as linear distances along the shaft in the illustration.
• Use basic algebra: Total length = A + B + C + D + X.
💭 Think About
• Look carefully at the arrows in the illustration: which parts of the shaft are covered by A, B, C, and D, and which remaining part must be X?
• Once you write an equation for the total length (42 in.) in terms of A, B, C, D, and X, how can you isolate X on one side?
• After finding X, compare your result to the answer choices and think about whether it makes sense visually compared to A and B.
✅ Before You Answer
• Add A, B, C, and D together carefully, paying attention to the fraction in D = 8 3/16 in.
• Convert any fractions to decimals (or all decimals to fractions) before doing the subtraction so you don’t mix formats.
• After solving, confirm that A + B + C + D + X comes back to 42 inches when you plug your value of X back in.